Mineral oil compositions metal alkyl ester tetrapropenylsuccinates

ABSTRACT

Mineral oil compositions are provided containing a small amount sufficient to inhibit corrosive deterioration of metal surfaces of a member of the group consisting of metal alkyl ester tetrapropenylsuccinates and alkoxy metal alkyl ester tetrapropenylsuccinates, the metal component of said tetrapropenylsuccinates being selected from the class consisting of Groups I, II and III of the Periodic Table of the Elements.

United States Patent Gee et a1.

[4 1 Jan. 18, 1972 MINERAL OIL COMPOSITIONS CONTAINING METAL ALKYL ESTER TETRAPROPENYLSUCCINATES [72] Inventors: Paul Y. C. Gee, Woodbury; Harry J. An-

dress, Jr., Pitman, both of NJ.

1965, abandoned.

[52] US. Cl ..44/68, 44/70, 252/389 [51] Int. Cl. ..C01l 1/14 [58] Field of Search ..44/68, 70; 252/389; 260/429.9

- [56] References Cited UNITED STATES PATENTS 2,458,425 1/1949 2,851,417 9/1958 3,247,110 4/1966 3,271,310 9/1966 Le Seur ..260/429.9

Primary ExaminerDaniel E. Wyman Assistant ExaminerMrs. Y. H. Smith Attorney0swald G. Hayes, Andrew L. Gaboriault, Raymond W. Barclay and Benjamin 1. Kaufman [5 7] ABSTRACT Mineral oil compositions are provided containing a small amount sufficient to inhibit corrosive deterioration of meta] surfaces of a member of the group consisting of metal alkyl ester tetrapropenylsuccinates and alkoxy metal alkyl ester tetrapropenylsuccinates, the metal component of said tetrapropenylsuccinates being selected from the class consisting of Groups 1, 11 and III of the Periodic Table of the Elements.

7 Claims, No Drawings MINERAL OIL COMPOSITIONS METAL ALKYL ESTER TETRAPROPENYLSUCCINATES CROSS-REFERENCE TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention which is a continuation-in-part of our application Ser. No. 427,181 filed Jan. 21, I965, now abandoned, relates to improved mineral oil compositions and, in one of its aspects relates more particularly to improved mineral oil comin the form of petroleum distillate fuel oils, containing from about I to about 200, and preferably from about 5 to about 50, pounds per l,000 barrels of liquid hydrocarbon of the aforementioned metal salts, which may comprise either a metal alkyl ester tetrapropenylsuccinate or an alkoxy metal alkyl ester tetrapropenylsuccinate.

The metal salts contemplated herein are, in general, prepared by reacting one mole of a metal alkoxide with from about I to about 3 moles of tetrapropenylsuccinic anhydride 0 or alkyl esters of tetrapropenylsuccinic acid. The reaction is carried out at an elevated temperature, preferably at a temperature from about 100 C. to about 175 C, The following equations illustrate the general formation of the metal salt positions in the form of liquid hydrocarbons that are normally products which are either metal alkyl ester tetrapropenylsuc' susceptible of causing deterioration of metal surfaces by corrosion. Still more particularly, in this aspect, the invention relates to improved liquid hydrocarbons in the form of petroleum distillate hydrocarbon fuel oils, which, in their uninhibited state, tend to rust metal surfaces, clog screens and to emulsify 2 under the conditions of use.

2. Description of the Prior Art It is well known that certain types of mineral oil compositions are normally susceptible of causing deterioration by corrosion when coming into contact with various metal surfaces. For example, it is known that liquid hydrocarbons in the form of fuel oils are prone to form sludge or sediment during periods of prolonged storage. Such sludge or sediment have an adverse effect on burner operation by reason of their tendency to clog screens and nozzles. In addition to sediment and sludge which are formed during storage, most fuel oils contain other impurities such as rust, dirt and entrained water. Such impurities tend to settle out on equipment parts such as nozzles, screens, filters and the like, thereby causing clogging and deterioration and failure of equipment. Another undesirable characteristic of petroleum fuel oils is objectionable emulsions.

A further incident to the sludge formation in the handling of distillate fuels is the breathing of storage vessels. This results in the accumulation of considerable amounts of water in the tanks and thereby causes rusting and consequent deterioration of equipment. Thus, when the fuel is removed for transportation, sufficient water may be carried along to result in rusting of ferrous metal surfaces in pipelines, tankers, and other equipment.

Heretofore, in the case of fuel oils, and other organic compositions subject to causing the aforementioned deterioration, it has been the practice to overcome such difficulties through the use of a separate additive for each purpose, i.e., employing a sediment inhibitor, an antiscreen-clogging agent, an antirust agent and an emulsion inhibitor. The use of several additives, however, gives rise to problems of additive compatibility, thus restricting the choice of additive combinations. In addition, of course, the use of a plurality of additives unduly increases the cost of the fuel. It is, therefore, highly desirable from a commercial standpoint to overcome the aforementioned difficulties through the use of a single additive agent, which is effective against rusting of metal surfaces, sediment formation, screen and nozzle clogging, and emulsification.

SUMMARY OF THE INVENTION It has now been found that all of the aforementioned difficulties, viz rusting, sedimentation, screen clogging and emulsification can be overcome by the use of a single additive agent. In this respect, it has now been found that mineral oil compositions, particularly liquid hydrocarbons in the form of petroleum distillate fuel oils, containing minor amounts of metal salts of the group consisting of metal alkyl ester tetrapropenylsuccinates and alkoxy metal alkyl ester tetrapropenylsuccinates, are effectively inhibited, simultaneously. against all of the aforementioned deterioration difficulties.

The present invention, in general, provides improved mineral oil compositions, and preferably liquid hydrocarbons their tendency to form 1 cinates or alkoxy metal alkyl ester tetrapropenylsuccinates:

in which R is a tetrapropenyl group having the following structure:

and It. is an alkyl group preferably having from 1 to about l8 carbon atoms.

The mineral oil compositions improved in accordance with the present invention may be any materials that are normally susceptible of causing deterioration of metal surfaces by corrosion or by any of the other aforementioned factors, in the manner previously described. A field of specific applicability is the improvement of liquid hydrocarbons in accordance with the present invention, boiling from about 75 F. to about 750 F. Of particular significance is the treatment of petroleum distillate fuel oils having an initial boiling point from about 75 F. to about 135 F., and an end boiling point from about 250 F. to about 750 F. It should be noted, in this respect, that the term distillate fuel oils" is not intended to be restricted to straight-run distillate fractions. The distillate fuel oils can be straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well known commercial methods, such as acid or caustic treatment, hydrogenation, solventrefining, clay treatment, and the like.

The distillate fuel oils are characterized by their relatively low viscosity, pour point and the like. The principal property which characterizes the contemplated hydrocarbons, however, is their distillation range. As hereinbefore mentioned, this range will lie between about 75 F. and about 750 F. Obviously, the distillation range of each individual fuel oil will cover a narrower boiling range falling, nevertheless, within the above-specified limits. Likewise, each fuel oil will boil substantially continuously throughout its distillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2, and 3 fuel oils used in heating and as Diesel fuel oils, gasoline and the jet combustion fuels. The domestic fuel oils generally conform to the specifications set forth in ASTM Specification D396--48T. Specifications for Diesel fuels are defined in ASTM Specification D975-48T. Typical jet fuels are defined in Military Specification MlL-F5624B.

DESCRIPTION OF SPEClFlC EMBODIMENTS The following examples will serve to illustrate the preparation of the aforementioned metal salts of the present invention, which are either metal alkyl ester tetrapropenylsuccinatcs or alkoxy metal alkyl ester tetrapropenylsuccinates, and to demonstrate the effectiveness thereof in rendering mineral oil compositions, and particularly liquid hydrocarbons, e.g., petroleum hydrocarbon distillate fuels, thermally stable. It will be understood that it is not intended that the invention be limited to the particular compositions shown or to the operations or manipulations involved. Various modifications of these additives, as previously described, can be employed and will be readily apparent to those skilled in the art.

EXAMPLE 1 A mixture of 133 grams (0.5 mole) of tetrapropenylsuccinic anhydride, 6.08 grams (0.25 mole) of magnesium in the form of a magnesium methylate solution and 139 grams of a solvent-refined petroleum mineral oil obtained from a Mid-Continent crude, as a diluent, was gradually heated to 140 C. with stirring, and was held at that temperature until all the menthanol had distilled out, viz for a period of about 1 hoursv The resulting reaction product was filtered through Hyflo- Super-Cel clay. The final filtered product, viz the magnesium methyl ester tetrapropenylsuccinate, containing 50 percent of the aforementioned diluent, was clear and fluid at room temperature.

Found Estimated EXAMPLE 2 Analysis above-described mineral oil diluent and filtered through the aforementioned clay. The final filtered product, viz the methoxy magnesium methyl ester tetrapropenylsuccinate, containing 66% percent of the aforementioned mineral oil diluent, was clear and fluid at room temperature.

Analysis Estimated Found EXAMPLE 3 A mixture of 266 grams (1 mole) of tetrapropenylsuccinic anhydride, diluted with 668 grams of the same mineral oil diluent employed in example 1, and 68.5 grams (0.5 mole) of barium in the form of a barium methylate solution was gradually heated to C. and was held at that temperature until the methanol stopped coming over, viz for a period of about 2 hours. The resulting reaction product was filtered through the aforementioned clay. The final filtered product, viz the barium methyl ester tetrapropenylsuccinate, containing 66% percent of the aforementioned mineral oil diluent, was clear and fluid at room temperature.

Analysis Estimated Found %Ba 6.6 6.7

EXAMPLE 4 A mixture of 266 grams (1 mole) of tetrapropenylsuccinic anhydride, diluted with 300 cc. of xylene, and 23 grams 1 mole) of sodium in the form of a sodium methylate solution, was gradually heated to 150 C., and was held at that temperature for 2 hours to form the sodium methyl ester tetrapropenylsuccinate. To the sodium methyl ester tetrapropenylsuccinate thus formed, was added at room temperature with stirring, 78 grams (0.5 mole 15 percent excess) of zinc chloride, previously dissolved in 300 cc. of methanol. The mixture was gradually heated to 150 C., and was held at that temperature for a period of 2 hours to insure the complete formation of the zinc salt. The resulting reaction product, being viscous at room temperature, was diluted with about 700 cc. of benzene, filtered through the aforementioned clay, and distilled to 150 C. under house vacuum. The residue, was found to weigh 323 grams, theory 329 grams, and was diluted with 323 grams of the above-described mineral oil diluent. The final product, viz the zinc methyl ester tetrapropenylsuccinate, containing 50 percent of the aforementioned mineral oil diluent, was dlear and fluid at room temperature.

Analysis Estimated Found EXAMPLE 5 A mixture of 133 grams (0.5 mole) of tetrapropenylsuccinic anhydride, diluted with 150 cc. of xylene, and l 1.5 grams (0.5 mole) of sodium in the fonn of a sodium methylate solution, was gradually heated to 150 C. with stirring, and was held at that temperature for a period of 2 hours to form the sodium methyl ester tetrapropenylsuccinate. To the sodium methyl ester tetrapropenylsuccinate thus formed, was added at room temperature with stirring 33 grams (0.25 mole 15 percent excess) of calcium chloride, previously dissolved in 200 cc. of methanol. The mixture was gradually heated to 150 C., and was held at that temperature for a period of 2 hours to form the calcium methyl ester tetrapropenylsuccinate. The resulting reaction product, being viscous at room temperature, was diluted with benzene, filtered through the aforementioned clay and distilled to 150 C. under house vacuum. The residue was diluted with 286 grams of the above-described mineral oil diluent. The final product, viz the calcium methyl ester tetrapropenylsuccinate, containing approximately 66% percent of the aforementioned mineral oil diluent, was clear and fluid at room temperature.

Found A mixture of 133 grams (0.5 mole) of tetrapropenylsuccinic anhydride, 100 grams (0.5 mole) of tridecyl alcohol, 2.3 grams 1 percent) of p-toluene sulfonic acid monohydrate and 200 cc. of xylene was stirred at about 140 C. for a period of 3 hours to form the tridecyl ester tetrapropenylsuccinic acid. To the tridecyl ester tetrapropenylsuccinic acid was added at room temperature with stirring 1 1.5 grams (0.5 mole) of sodium in the form of a sodium methylate solution. The mixture was gradually heated to 150 C. to form the sodium tridecyl ester tetrapropenylsuccinate. To the sodium tridecyl ester tetrapropenylsuccinate was added at room temperature with stirring 44 grams (0.25 mole grams excess) of zinc chloride, previously dissolved in 200 cc. of methanol. This mixture was gradually heated to 150 C. and was held at that temperature for a period of 1 hour to form the zinc tridecyl ester tetrapropenylsuccinate. The reaction mixture, being viscous at room temperature, was diluted with benzene, filtered through the aforementioned clay and distilled to 150 C. under house vacuum. The residue which weighed 241 grams, theory 249 grams, was diluted with 241 grams of the above described mineral oil diluent. The final product, viz the zinc tridecyl ester tetrapropenylsuccinate, which contained 50 percent of the aforementioned mineral oil diluent was clear and fluid at room temperature.

Analysis Estimated Found EXAMPLE 7 A mixture of 133 grams (0.5 mole) of tetrapropenylsuccinic anhydride, 121 grams (0.5 mole) of hexadecyl alcohol, 2.6 grams (1 percent) of p-toluene sulfonic acid monohydrate and 125 cc. of toluene, was stirred at 140 C. for a period of 3 hours to form the hexadecyl ester tetrapropenylsuccinic acid. To the hexadecyl ester tetrapropenylsuccinic acid thus formed, was added at room temperature with stirring 11.5 grams (0.5 mole) of sodium in the form of a sodium methylate solution. The mixture was gradually heated to 150 C. to form the sodium hexadecyl ester tetrapropenylsuccinate. To the sodium hexadecyl ester tetrapropenylsuccinate thus formed was added at room temperature with stirring 44 grams (0.25 mole 10 grams excess) of zinc chloride previously dissolved in 200 cc. of methanol. The mixture was then gradually heated to 150 C. and was held at that temperature for a period of 2 hours to insure the complete formation of the zinc hexadecyl ester tetrapropenylsuccinate. The resulting reaction product, being viscous at room temperature, was diluted with benzene, filtered through the aforementioned clay and distilled to 150 C. under house vacuum. The residue weighed 260 grams, theory 266 grams, and was diluted with 260 grams of the aforementioned mineral oil diluent. The final product, viz the zinc hexadecyl ester tetrapropenylsuccinate, containing 50 percent of the aforementioned mineral oil diluent, was clear and fluid at room temperature.

Estimated Found Analysis X Zn EXAMPLE 8 product, viz the aluminum methyl ester tetrapropenylsuccinate, containing approximately 66% percent xylene, was clear and fluid at room temperature.

Analysis %Al Estimated Found SCREEN CLOGGlNG The anti-screen-clogging characteristics of a fuel oil were determined as follows. The test is conducted using a Sundstrand V3 or S1 home fuel oil burner pump with a self-contained IOO-mesh Monel metal screen. About 0.05 percent, by weight of naturally formed fuel oil sediment, composed of fuel oil, water, dirt, rust, and organic sludge is mixed with 10 liters of the fuel oil. This mixture is circulated by the pump through the screen for 6 hours. Then, the sludge deposit on the screen is washed off with normal pentane and filtered through a tared Gooch crucible. After drying, the material in the Gooch crucible is washed with a 50-50 (volume) acetone-methanol mixture. The total organic sediment is obtained by evaporating the pentane and the acetone-methanol filtrates. Drying and weighing the Gooch crucible yields the amount of inorganic sediment. The sum of the organic and inorganic deposits on the screen can be reported in milligrams recovered or converted into percent screen clogging.

The metal salt additives of the aforementioned examples 1 through 8 were incorporated in a fuel oil blend comprising, by weight, approximately 60 percent distillate stock obtained from continuous catalytic cracking and approximately 20 percent straight-run distillate stock, having a boiling range of from about 320 F. to about 640 F., and being a practical No. 2 fuel oil. The results obtained are set forth in the following table 1.

The test used to determine the sedimentation characteristics of the fuel oils is the 1 10 F. Storage Test. In this test, a 500-milliliter sample of the fuel oil under test is placed in a convected oven maintained at F. for a period of 12 weeks. Then, the sample is removed from the oven and cooled. The cooled sample is filtered through a tared asbestos filter (Gooch crucible) to remove insoluble matter. The weight of such matter in milligrams is reported as the amount of sediment. A sample of the blank, uninhibited oil is run along with a fuel oil blend under test. The effectiveness of a fuel oil containing an inhibitor is determined by comparing the weight of sediment formed in the inhibited oil with that formed in the uninhibited oil.

The method used for testing antirust properties of gasolines was the ASTM Rust Test D-665 operated for 48 hours at 80 F. using distilled water. This is a dynamic test that indicates the ability to prevent rusting of ferrous metal surfaces in pipelines, tubes, etc. Blends of the additives described in the fuel oil, such as employed in accordance with the tests disclosed in tables 1 and 11, were subjected to the ASTM Rust Test D-665. The results obtained are set forth in the following table 111.

TABLE 111 ASTM Rust Test D-665 Concn. Rust test lnhibitors p.p.m. Result Blank fuel blend Fail Blank fuel blend ex. l 25 Pass Blank fuel blend ex. 3 10 Pass Blank fuel blend ex. 4 10 Pass Blank fuel blend ex. 5 Pass Blank fuel blend ex. 6 25 Pass Blank fuel blend ex. 7 25 Pass Additional mineral oil blends were prepared. Each blend contained a small amount of the aforementioned additives described in the examples. The base oil employed was a highly solvent-refined mineral lubricating oil having 31 APl gravity and a Saybolt Universal viscosity of 150 seconds at 100 F. This is a typical steam turbine lubricating oil. These blends were subjected to the aforementioned ASTM Rust Test D-665. The results obtained are set forth in the following table lV.

TABLES 1V ASTM Rust Test D-665 Rust test Result Concn.

Inhibitors Wt. k

Blank light turbine oil 0 Fail Blank light turbine oil ex. 1 03 Pan Blank light turbine oil ex. 2 0.3 Pa: Blank light turbine oil ex. '3 03 Pan Blank light turbine oil ex. 4 0.1 Pass Blank light turbine oil ex. 5 03 Pass Blank light turbine oil ex. 6 0.2 Pass Blank light turbine oil ex. 7 0.2 Pass Blank light turbine oil ex. 8 0.3 Pass It will be apparent, from the data set forth in tables 1 through N, that the metal alkyl ester tetrapropenylsuccinates and the alkoxy metal alkyl ester tetrapropenylsuccinates of the present invention are highly effective in reducing sedimentation, screen clogging, and in inhibiting corrosion of metal surfaces. As will be understood, results will vary among the specific materials employed. In order to accomplish any given improvement, many of the additives can be used in relatively minor proportions, as, for example, in the prevention of corrosion. If, on the other hand, it is desired to accomplish all the aforementioned beneficial results, this can be carried out at the practical additive concentrations of from 5 to about 50 pounds per 1,000 barrels of liquid hydrocarbon.

ln commonly assigned US. Pat. No. 2,851,417 and US. Pat. No. 3,247,110, there are disclosed the use of certain amides of tetrapropenylsuccinic acid as fuel oil additives. These amides can be favorably contrasts with the use of the above-described specified esters of tetrapropenylsuccinic acids in the mineral oil compositions of the present invention; however, a marked superiority in water-separation index is realized for the specified ester tetrapropenylsuccinic acids of the present invention over the amide acids of the aforementioned patents when subjected to the standard ASTM D2550- 66T (page 943) test. This is a water-separation index method for use in rating the ease with which a fuel or fuel additive combination will release entrained or emulsified water when passed through a coalescer-type water separator. The test provides a measure of the presence of surfactant agents in the fuel. These are known to affect the ability of filter coalescers to separate free water from aviation fuels. The water-separation index is a numerical rating indicating the ease of separating water from fuel by coalescence. The higher the numerical rating, the more desirable the fuel. In the use of this test, it is found, from a practical standpoint, that fuel additives, in general, tend to cause some degree of water-separation so that a rating of or higher is considered to reflect an insignificant, and therefore acceptable, degree of water-separation. Ideally, the least amount of water-separation is realized when additives are completely absent from the fuel.

With the above in view, comparative data were obtained evaluating the aforementioned waterseparation index, according to ASTM D2550-66T, of l the complex magnesium methoxy salt of naphthenic acid containing two equivalents of magnesium, prepared in accordance with example 12 of the aforementioned US. Pat. No. 2,851,417; (2) the methoxy magnesium salt of the mono-amide tetrapropenylsuccinic acid, prepared in accordance with example 10 of the aforementioned U.S. Pat. No. 3,247,l l0; and (3) the methoxy magnesium methyl ester tetrapropenylsuccinate, prepared in accordance with the foregoing example 2 of the present application. Each additive was incorporated in a test fuel comprising a blend of percent distillate stock obtained from continuous catalytic cracking and 20 percent straight-run distillate stock, and having a boiling range of from about F. to about 450 F. Each blend was then subjected to the aforementioned water-separation index test. The results obtained are set forth in the following table V.

TABLE V Water-separation index Modified (ASTM D2550-66T P. 943) Cunc. lh./

Inhibitor I000 bhls. Rating Uninhibited fuel 85 Uninhibitcd fuel ex. 2 l 76 uninhibited fuel ex. l2 ofU.S. 2,851,4l7 1 45 Uninhihitcd fuel ex. 10 ofU.S. 3,247.] N) l 24 ficient to inhibit said deterioration of a member of the group consisting of metal alkyl ester tetrapropenylsuccinates and alkoxy metal alkyl ester tetrapropenylsuccinates, the metal component of said tetrapropenylsuccinates being selected from the class consisting of Groups, I ll and III of tile Periodic Table of the Elements.

2. The composition of claim 1 wherein said mineral oil is a liquid hydrocarbon comprising a petroleum distillate fuel oil having an initial boiling point from about 75 F. to about F. and an end boiling point from about 250 F. to about 750 F.

3. The composition of claim 1 wherein said tetrapropenylsuccinate is present in an amount from about 1 to about 200 pounds per 1,000 barrels of the total of said composition.

4. The composition of claim 1 wherein said tetrapropenylsuccinate is present in an amount from about 5 to about 50 pounds per 1,000 barrels of the total of said composition.

5. The composition of claim 1 wherein said mineral oil comprises a jet fuel.

6. The composition of claim 1 wherein said mineral oil comprises a gasoline.

7. The composition of claim I wherein said mineral oil comprises a turbine fuel.

" D STATES ?ATENT OFFICE CETIFICATE OF CORECTION Patent No. 35, Dated January 18, 1972 Inventor) PAUL Y. C. GEE and HARRY J. ANDRESS, JR.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line L? "Tests" should read Screen Clogging Tests Column 7, line 5% under "Concn. ppm. (EX. L) "l0 should read 25 Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

ROBERT GOI'ISCHALK Commissioner of Patents EDWARD MJLETCHER, JR. Attesting Officer 233 3? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 35, Dated January 18, 1972 Inventor(s) Y. C. and J. JR.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line L? "Tests" should read Screen Clogging Tests Column 7, line 5 L under Concn. ppm. (EX. L) "10" should read 25 Signed and sealed this 13th day of June 1972.

(SEAL) Attes'b:

ROBERT GOTTSCHALK I Commissioner of Patents EDWARD M.FLETCHER, JR. Attesting Officer 

2. The composition of claim 1 wherein said mineral oil is a liquid hydrocarbon comprising a petroleum distillate fuel oil having an initial boiling point from about 75* F. to about 135* F. and an end boiling point from about 250* F. to about 750* F.
 3. The composition of claim 1 wherein said tetrapropenylsuccinate is present in an amount from about 1 to about 200 pounds per 1,000 barrels of the total of said composition.
 4. The composition of claim 1 wherein said tetrapropenylsuccinate is present in an amount from about 5 to about 50 pounds per 1,000 barrels of the total of said composition.
 5. The composition of claim 1 wherein said mineral oil comprises a jet fuel.
 6. The composition of claim 1 wherein said mineral oil comprises a gasoline.
 7. The composition of claim 1 wherein said mineral oil comprises a turbine fuel. 